A complication is that there have been some reports of a recent OTA update that adds a startup script that deletes the diags /usr/local folder containing the dropbear files needed for SSH. This requires a fastboot reflash to restore them.

It is worth making a data.tar.gz that contains all the /usr/local files for diags, so after OTA is naughty to you, just drop the data.tar.gz (and ENABLE_DIAGS) on the USB drive and reboot to diags, and SSH should work again.